Boom.



J. R. MOGIFFERT.

Boom. t APPLIATION FILED DBO. 7,71910. 988,124. Patented Mar. 28, 1911.

r-c; IF 72 f; O f

.1.. Q1 l 4 f? 12 JOHN R. MCGIFFERT, OF DULUTI-I, MINNESOTA, ASSIGNOR TO CIJYDE IRON WORKS, OF DULUTH, MINNESOTA, A CORPORATION 0F MINNESOTA.

BOOM.

Specification of Letters Patent.

Patented Mar. 28, 19511.

Application filed December 7, 1910; Serialc No. 596,603;A

To all whom it may concern:

Be it known that I, JOHN McGirrER'r, a citizen of the United States, and a resident of Duluth, county of St. Louis, and State j of Minnesota, have invented a new and useful Improvement in Booms, of which the following isa specification, the principle of the invention being herein explained and the best mode in which I. have contemplated applying' that principle, so asv to distinguish it from other inventions.

In the construction of certain types of boom, as, for example, aV bo-om comprising side members movably secured to each other at their outer ends such as the boom em'- ployed in the machine forlogging that forms the subject matter of my U. S. Patent- No. 964,534, dated July 19, 1910, it has been found desirable to provide forv a certain amount of lateral sway of such members, and thus of the boom. In fact such pro-- vision may bef found advantageous even in the case of a boom in which the side members are relatively xedly secured together at t-heir outer ends, as in the more familiar construction. lVhile a degree of flexibility in this particular may be secured by simply making the connection of the' lower ends of the respective boom members with the support or socket on the machine frame or base sufficiently loose to permit of a slight lateral swaying, as is described and claimed in the above named patent, I have devised a special construction of socket, or connection for such lower ends of the boom members, which gives the desired flexibility without detracting in any wayV from the security of the structure and without any undue looseness of parts.

Said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawing and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawing: Figure l is a broken plan View of a boom such as that first above described, with my present improvements incorporated therein; Fig. 2 is a side elevational view of the lower end of such boom; and Fig. 3 is a transverse section; Fig. 4 longitudinal section, there- 1 through, taken on the lines and 444,

respectively, Fig. l.

e The boom proper, comprising the present instance twe side members I, the outer ends of which are connected by a trans- 1 versely disposed member 2 and pivot pins l2, so as to permit of rela-tive movement between said ends, isA not of itself o-f interest and hence need not be further described. It isv to the spaced supports 3' on the base or frame 4, of the machine, to which the lower end of said boom members are secured, that attention. is desired. Each of these supports 3 comprises a plate formed with two similar, upwardly and forwardly projecting ears 5I pierced by transverse apertures 6 that are alined to receive' pin 7. Between said ears, and pivotally held inl place by such pin,` is a swivel bar 8 which it will thus be' seen is capable of an oscillatory movement about the axis of the pini. This swivel bar is inl turn oscillatorily secured in the lowerl end of the i corresponding boom member l, so as tox permit of a twisting, or rotative', movement of the latterA about the longitudinal axis of the bar, which is` obviously right-angularly related to the of the pinl 7. Said bar is secured to the boom member by being fitted between two blocks 9, made in halves for Vthis purpose, which are inserted between the two channel b'a'rs that are utilized in the construction of the particular boom member hereV chosen for illustrative purposes. These blocks 9 are securely connected with such channels by means of bolts 10, the channels themselves being held together by means of plates l1, riveted to their flanges. Other modes of rotatably securing the swivel members may of course be .utilized where the construction of the boom member varies from the construction in question.

By means of the construction and arrangement of the parts just described, the side members of the boom are not only permitted an oscillatory movement in vertical planes about the pins 7 in the supports 3 on the base, but said members are also permitted an -independent movement about the central longitudinal axes defined by the axes of the respective swivel bars 8. The boom structure as a whole is accordingly able to accommodate itself to the distorting effects of the strain of the skidding, or lifting cables passing over its outer end, such as is bound to occur where the load is heavy, even it the guying cables are lirmly secured. indeed this twisting action has been found su'liicient to cause the side members of the boom to collapse, where provision is not made to accommodate the structure to this distortion; but by the present construction ot swivel connection between the lower ends of the boom and the base or support upon the latter, l have entirely overcome this difculty.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the itollowing claims or the equivalent of such stated means be employed.

l therefore particularly point out and distinctly claim as my invention l. ln mechanism ot the character described, the combination with spaced supports; of a boom comprising side members respectively secured to said supports at their lower ends so as to be pivotal. about an axis substantially longitudinal ot the correspond ing member.

Q. ln mechanism of the character described, the combination with spaced supports; of a boom comprising side members respectively secured to said supports at their lower ends so as to be pivotal about rightangularly related axes, substantially as described.

3. ln mechanism of the character described, the combination with spaced supports; of a boom comprising side members respectively secured to said supports at their lower ends so as to be pivotal about two axes, one lying transversely of said supports, the other longitudinally of the member.

Ll. In mechanism ot the character described, the combination with spaced supports; of a boom comprising side members respectively secured to said supports at their lower ends so as to be pivotal about rightangularly related axes, the other ends of said members being connected but movable relatively to each other.

5. ln mechanism of the character described, the combination with spaced supports consisting of plates formed with ears, and bars oscillatorily secured to said ears; of a boom comprising side members swiveled upon said bars at their lower ends.

G. ln mechanism oi the character described, the combination with spaced supports consisting of plates formed with ears, and bars oscillatorily secured to said ears; of a boom comprising side members swiveled upon said bars at their lower ends, the other ends of said members being connected but movable relatively to each other.

7. ln mechanism ot the character described, the combination with spaced supports consisting of plates each formed with two ears, and a swivel bar pinned at one end between said ears; of a boom comprising side members pivotally secured at their lower ends to said bars, respectively, the outer ends of said members being connected but movable relatively to each other.

Signed by me this 30th day ot November, 1910.

JOHN R. MCGIFFERT.

fit-tested by- H, C. lVns'rRoM, M. lW. Lnrr.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C." 

